The use of glyoxal and of thermosetting resins to impart crease resistance and dimensional stability to textile materials and to insolubilize the binders in paper coating compositions is well-known. These resins, known as "aminoplast resins," include the products of the reaction of formaldehyde with such compounds as urea, thiourea, ethylene urea, dihydroxyethylene urea, melamines, or the like. A serious drawback to the use of such materials is that they contain free formaldehyde. This is present during the preparation and storage of the agent and its use in treating textiles or paper, on the treated fabric or paper, and on the finished garments. Also, when the fabrics or garments made therefrom are stored under humid conditions, additional free formaldehyde is produced.
The presence of even less than one percent of free formaldehyde, based on the total weight of the product, is undesirable, not only because of its unpleasant odor, but because it is an allergen and an irritant, causing severe reactions in the operators who manufacture the agent and who treat and handle the treated fabrics and paper and to persons who handle and wear garments fabricated from the treated fabrics.
These problems associated with the presence of free formaldehyde on treated fabrics are well-known and considerable efforts have been made to produce formaldehyde-free textile treating agents and insolubilizers for the binders in paper coating compositions.
Glyoxal is a highly reactive monomer which cures quickly and has excellent crosslinking and insolubilizing properties. As a result of this rapid crosslinking of glyoxal and binder, however, the viscosity of the composition increases so rapidly and is so great that the composition cannot be used. Frequently glyoxal-solubilized coatings gel completely, particularly in high solids formulations; gelling can occur also in moderate or low solids formulations if they are not used promptly. Thus in situations where it is required that the viscosity remain stable for many hours, for example when high-solids coatings are to be applied by blade coating techniques, a glyoxal system is unsuitable. Formaldehyde-free agents for treating textiles have been disclosed in U.S. Pat. Nos. 4,285,690 and 4,332,586 and formaldehyde-free insolubilizers for binders in paper coating compositions have been disclosed in U.S. Pat. No. 4,343,655.